Improvement in sewing-machines



L. B. MILLER. 4S@Wing-M:whine. No. 214,513. Patented April 22,1879..

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MPETERS, PHOT LITHDG UNITED STATESIPATENT OFFICE.

LEBBEUS B. MILLER, OF ELIZABETH, NEW JERSEY, ASSIGNOR TO THE SINGER MANUFACTURING COMPANY, OF NEV YORK CITY.

IMPROVEMENT IN SEWING-MACHINES.

Specilication forming part of Letters Patent No. 214,513, dated April 22, 1879; application :filed l November 17, 1877.

To all whom it may concern:

Be it known that I, LnBBi-Ius BALDWIN MILLER, of Elizabeth, in the county of Union and State of New Jersey, have made an invention of certain new and useful Improvements in Sewing-Machines; and that the following is a full, clear, and exact description and specification of the same.

This invention has reference more particularly to the devices connected with the head of the bracket-arm or needle-arm of sewing- Inachines; and its objects are to facilitate the regulation of the tension upon the needlethread, and to impart a symmetrical appearance to the devices connected with the said head.

To these ends my invention consists of the combination and arrangement of certain devices, which are specified in detail in the claim at the close of this specication.

In orderv that the invention may be fully uuderstood, I have represented in the accompanying drawings, and will proceed to describe, the best mode in which Ihave thus far embodied my invention in a workin g machine.

Figure 1 of said drawings represents aface view of the head oi' the needle-arm of a Singer sewing-machine with my improvements applied thereto. Fig. 2 represents a sectionalview of the same. Fig. 3 represents an edge view of the same. Fig. 4 represents a transverse section of some of the parts at the line 1v of Fig. l.

The tension dev ice or thread-tension (represented in the said iigures) lconsists of two perforated disks, a a', mounted upon a movable bolt, b, which passes through their centers into the head C of the needle-arm. One of these disks, a, rests at its back against the face of the said head C.

The other disk, a', may be drawn with greater or less force toward the first disk, a, by means of the bolt b, so as to produce a greater or less frictional resistance to the free movement of the needle-thread inserted between the adjacent faces of the two disks.

In order to apply the force the inner end oi' the bolt bis grooved to receive the forked endl of a lever-spring, D, which is held in an upright position within the cavity of the head,

its fulcrum-point being perforated to admit the screw c, by which it is held in place. The upper arm of this lever-spring I) is inclined, as seen in Fig. 4, and a conical pointed adjusting-screw, F, is provided to operate against this inclined arm.

The screw is inserted in a screw-threaded hole formed in the top of the head C, so that the screw-head g is in a very convenient position to be' turned by the operator of the niachine. This tension-screw is also arranged at 1 the side oi. the needle-bar H opposite that at which the regulating-screw I 'of the presserfoot J is arranged, the said needle-bar being arranged centrally of the said head, so that the two regulating-screws present a symmetrical appearance.

The. regulating-screw I of the presser-foot operates upon a spring, Z, so as to compress it or permit its extension, and thus regulate the force acting to depress the presser-footJ upon the article being sewed. The inner end of the regulating-screw F of the thread-tension, being conical, operates, when screwed downward upon the incline of the lever tension-spring, as a wedge to move the upper arm thereof laterally, and thus cause the lower arm to act with greater force in pulling the outer tensiondisk, a', toward the inner disk, a. When, on the otherh and,this regulatin g-screw is screwed upward, the forceexerted by the lever-spring is relaxed.

The invention may also be embodied by .substituting a wheel thread-tension in place of tension-disks. In such case the grooved teusion-wheel, around which the needle-thread is coiled, may be set upon the movable bolt b in placeof the tension-disks, and a frietional disk of cloth (or other material capable of exerting a frictional resistance to the turning of the wheel) may be insertedbetween the inner face or disk surface of the wheel and the face of the head C. Then the screwing of the adjusting-screwF downward will cause the leverspring to pull the tension-wheel against the cloth-disk with greater force, so that a greater frictional resistance will be exerted against the turning of the tension-wheel, and consequentlythe tension on the needle-thread will be increased. "When, on the other hand, the

regulating-screw is screwed upward, the force exerted by the lever-spring in pulling the of the sewing-machine, the tension-disks and the bolt thereof, the lever-spring, and the regu- Wheel-disk against the frictional or cloth disk lating-screw thereof, arranged at the top of is relaxed, and the tension upon the thread the head of the bracket-arm.

will be diminished.

The tension-Wheel and the frietional disk thus constitute substitutes in my combinations for the tension-disks first described.v

I claim as my invention- The combination'and arrangement, substantially as before set forth, of the bracket-arm Witness my hand this 29th day of October, A. D. `1877.

LEBBEUS BALDWIN MILLER.

Witnesses JNO. SCOTT, JAMES MEEHAN. 

